SpaceX Craft Rehearses Its Moves for Docking

The Space Explorations Technologies (SpaceX Dragon) cargo capsule makes its first pass by the International Space Station. (Video: Reuters/Photo: AP)

By

Andy Pasztor

Updated May 24, 2012 7:00 p.m. ET

A private unmanned spacecraft successfully completed a series of maneuvers around the international space station on Thursday, clearing the last major hurdle before a historic docking attempt planned for Friday.

The tests demonstrated that sensors, navigation equipment, communications links and computer-controlled propulsion systems aboard the Dragon capsule were working properly.

A private unmanned spacecraft appeared to flawlessly complete a series of maneuvers around the International Space Station Thursday, clearing the last major hurdle before a Friday docking attempt. Andy Pasztor has details on Lunch Break. Photo: Getty Images.

The so-called fly-under maneuver required the cone-shaped capsule—built and operated by Space Exploration Technologies Corp.—to catch up to, and then pass, the space station.

The highlight of the test, which occurred before 7:30 a.m. Eastern time, had the spacecraft float by about 1.5 miles below the station, as part of a rehearsal for the docking effort.

Government and company officials were unanimous in calling the flyby a huge success, boosting confidence that the company is ready for the tougher challenges it is expected to confront during the more delicate and risky docking operation.

National Aeronautics and Space Administration officials said preliminary indications were that Dragon's thrusters, laser-assisted sensors and thermal imaging instruments seemed to pass the preliminary rendezvous tests with flying colors, but analysis of the data was expected to continue through the day.

ENLARGE

A photograph of SpaceX's Dragon spacecraft taken from the International Space Station Thursday.
NASA

Earlier

Reaching Thursday's milestone means that the capsule apparently is poised to conduct the first linkup ever attempted between a private spacecraft and the 16-nation space station, a $100 billion orbiting laboratory.

The mission led by SpaceX, as the closely held Southern California company is called, is at the heart of President Barack Obama's drive to outsource the job of transporting cargo and astronauts to the space station to private industry by the second half of this decade. Dragon's expected visit would make it the first U.S. vehicle to arrive at the station in about a year, following the retirement of NASA's space shuttles.

SpaceX said Thursday that the spacecraft "has been performing well," and "has steadily completed one task after another" since going into orbit. But, in its statement, a spokeswoman stressed that "the most difficult aspects of the mission are still ahead."

Holly Ridings,
NASA's flight director, told reporters that "it was a great day in space" and the mission has been "very successful up to this point." She also said that regarding preparations on the station, "everything is set up and ready to go" for Friday.

Blast Off

The SpaceX Falcon 9 test rocket lifts off from the Cape Canaveral Air Force Station Tuesday. Reuters

John Couluris,
her counterpart at the company, said during the same briefing that "all Dragon systems checked out" and "we're looking good across the board." He said the capsule's fuel reserves are greater than projected, which could allow Dragon to make a second pass at the space station on Friday if the first docking attempt is aborted.

Dragon's rendezvous systems had never been tested before in the harsh conditions of space, with the station and the capsule racing around the Earth in tandem at about 17,000 miles an hour.

The toughest test of the SpaceX capsule is set to occur Friday, when the cargo capsule is expected to steadily move closer to the station in a weightless ballet with the larger craft.

If all goes well, astronauts
Donald Pettit
and his partners, observing and filming the capsule from inside the station, are supposed to manipulate a roughly 50-foot robotic arm to grab and pull the capsule into a docking port.

The station's crew, as well as engineers at SpaceX's mission-control center at its Hawthorne, Calif., headquarters, will be able to abort the sequence if they notice a problem. After the capsule hooks up with the station 240 miles above the earth, astronauts plan to retrieve about 1,000 pounds of provisions, including food and clothes.

At 5:58 a.m. EDT Thursday, following more than an hour spent fussing with balky monitors and calibration difficulties with video cameras aboard the space station, Mr. Pettit uttered the words NASA controllers were itching to hear: He could see Dragon from inside the station.

For the rest of Thursday, ground controllers plan to send Dragon on a wide loop around the space station, maintaining a separation of several miles as the spacecraft zips above and then falls behind the station. Some additional maneuvers and engine shut-off checks are expected before the final docking sequence.

Dragon is scheduled to leave the space station around the end of the month and splash down off the California coast.

Challenges of physically connecting Dragon with the space station are the toughest elements of the mission. The capsule, for instance, under some scenarios, will only have enough fuel for one docking attempt. The slightest speed or heading deviations from a detailed, preplanned approach path would be enough to immediately halt any docking attempt.

"There could be some wrinkles or hiccups that could complicate a berthing attempt," according to industry consultant
Charles Miller,
who helped devise part of NASA's commercial-space policies before leaving.

"This is not easy," Mr. Miller said in an interview, noting that resolving last-minute reasons for a wave-off on Friday could turn out to be expensive and time consuming.

Before Tuesday's picture-perfect launch,
Elon Musk,
Spacex's founder and chief executive, tried to damp expectations. Referring to operation of the rendezvous sensors and controls, he told CNN: "We need to prove that we have done it correctly."

But on Thursday, after initial analysis of data from the maneuvers, company officials indicated that everything still appeared on track for the docking attempt.

Rep. Chaka Fattah, a Pennsylvania Democrat who sits on a NASA appropriations subcommittee, said the mission isn't "just a single venture into space, but a change in the trajectory of how we think of space exploration."

Friday's activities will be captured on video and the images will be available on NASA's website, the same way visits by Russian, American and European supply ships have been shown in the past.

President Obama called SpaceX's chief executive Wednesday, the day after the successful launch. "The President just called to say congrats." Mr. Musk said via Twitter early Thursday, according to the Associated Press. "Caller ID was blocked, so at first I thought it was a telemarketer," his message joked.

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